PLATE LV. 
Trematopora (Orthopora) ornata. 
Page 184. 
See Plate 56. 
Fig. 1. An enlargement, showing the form and disposition of the cell apertures and the character of the 
interapertural space. (X 6 ) 
Hamilton group. Geneseo, N. Y. 
Trematopora (Orthopora) carinata. 
Page 179. 
See Plate 56. 
Fig. 2. An enlargement, showing the form and disposition of the cell apertures, the nodes between them, 
and the prominent ridges separating the ranges of apertures. (X 6.) 
Hamilton group. West Williams, Ontario, Canada. 
Trematopora (Orthopora) lineata. 
Page 181. 
See Plate 56. 
Fig. 3. An enlargement of a portion of a well-preserved frond, showing the form and arrangement of the 
cell apertures, and the granulose ridges separating the ranges of apertures. (X 6.) 
Fig. 4. An enlargement, showing the appearance of a frond when macerated. (X 6.) 
Fig. 5. An enlargement of a longitudinal section, showing the manner of growth of the cell tubes, and 
the intercellular space. (X 6.) 
Hamilton group West Hamburg, Erie county, N. F. 
Fig. 6. An enlargement of a portion of a sinuous frond having a greater number of ranges of apertures 
than tig 3. (X 6.) 
Hamilton group. Ogdens Ferry, Cayuga lake, N. Y. 
Acantiioclema sulcatum. 
Page 192. 
See Plate 56. 
Fig. 7. An enlargement, showing the form and disposition of the cell apertures, and the sharply angular, 
smooth ridges separating the ranges of apertures. 
Hamilton group. Darien Centre, Genesee county, N. Y. 
Trematopora (Orthopora) hexagona. 
Page 178. 
See Plate 56. 
Fig. 8. An enlargement, showing the form and disposition of the cell apertures, and the appearance of 
the interapertural space. (X 6.) 
Hamilton group. Eighteen-mile-creek, Erie county, N. Y. 
Trematopora (Orthopora) reticulata. 
Page 179. 
See Plate 56. 
Fig. 9. An enlargement, showing the form and arrangement of the cell apertures, and the granulose and 
nodose interapertural space. (X 6.) 
Hamilton group. Western New York. 
Trematopora (Orthopora) subquagrata. 
Page 177. 
See Plate 56. 
Fig. 10. An enlargment, showing the form and disposition of the cell apertures, and the polygonal areas. 
(X 6.) 
Hamilton group. Darien Centre, Genesee county, N. Y. 
Trematopora (Orthopora) elongata. 
Page 183. 
See Plate 56. 
Fig. 11. An enlargement of a longitudinal section, showing the manner of growth of the cell tubes, and 
the intercellular space. (X 6.) 
Hamilton group. Owasco Lake, N. Y. 
